Line erasing machines to remove painted lines and other markings from paved surfaces are known in the art. These line erasing machines may be of the walk-behind type which are moved by an operator walking behind the line erasing machine or of the self-propelled riding type on which an operator sits.
Walk-behind line erasing machines have a wheeled carriage beneath which is mounted a grinder having a plurality of radially extending grinding heads to contact the paved surface to be grinded. The grinding heads are maintained in a fixed plane relative to the carriage. A motor is supported on the carriage to actuate the grinder and rotate the grinding heads. A depth adjustment mechanism acts between the grinder and the carriage to allow the position of the grinder relative to the carriage to be adjusted. Conventional depth adjustment mechanisms allow the grinder to be moved to a desired position and then locked into that position. Thus, once the position of the grinder has been set, the plane of the grinding heads remains stationary with respect to the wheels of the carriage.
It is a well known fact that paved surfaces are not flat. Therefore, the grinders are locked in position with grinding heads maintained in a fixed plane relative to the carriage and the line erasing machine is wheeled over an uneven paved surface, one or more of the grinding heads may not be in constant contact with the paved surface as the grinding heads are rotated. This may require the operator to move the line erasing machine back and forth along the paved surface to be grinded until the marking is removed from the paved surface. Alternatively, the operator may stop the line erasing machine and reposition the grinder relative to the carriage by way of the depth adjustment mechanism to bring the grinding heads into contact with the paved surface. In either case, the time required to grind the paved surface is increased.
In addition, in some instances, because the grinding heads remain in a fixed plane relative to the carriage, if the paved surface is sufficiently uneven, the wheels of the carriage may be lifted from the paved surface by the grinding heads as they rotate and contact the paved surface. This may cause the line erasing machine to slide laterally from the marking on the paved surface requiring the operator to oscillate the machine back and forth across the paved surface until the marking is removed from the paved surface. Depending on the steering skill of the operator, the time taken to remove the marking from the paved surface will vary significantly. Accordingly, improved line erasing machines which overcome these disadvantages are sought.
It is therefore an object of the present invention to provide a novel grinding machine to remove markings from paved surfaces and a novel grinder for the same.